title: Intravascular injection during ultrasound-guided axillary block: negative aspiration can be misleading.
abstract: Needle visualization is an advantage of ultrasound-guided nerve blocks compared to traditional methods of nerve localization. However, visualization of local anesthetic spread is also important. During an ultrasound-guided axillary block, there was negative aspiration for blood. However, the absence of local anesthetic spread on ultrasound imaging suggested possible intravascular injection. The ultrasound transducer was removed from the patient's arm and venous blood was aspirated from the nerve block needle. Pressure applied to an ultrasound transducer can occlude venous structures making negative aspiration of blood unreliable for excluding intravascular needle placement.
authors.affiliation: Mayo Clinic Jacksonville, San Pablo Road, Jacksonville, FL 32224, USA. Robards.christopher@mayo.edu
authors.forename: Christopher
authors.initials: C
authors.lastname: Robards
authors.forename: Steven
authors.initials: S
authors.lastname: Clendenen
authors.forename: Roy
authors.initials: R
authors.lastname: Greengrass
mesh_terms: D000368:Aged; D000772:Anesthesia, Local / Q000379:methods; D000779:Anesthetics, Local / Q000008:administration & dosage; D001917:Brachial Plexus; D002387:Cataract Extraction / Q000379:methods*; D004867:Equipment Design; D005133:Eye Movements / Q000502:physiology; D005143:Eyelids; D005260:Female; D005385:Fingers; D006801:Humans; D007267:Injections / Q000295:instrumentation; D008297:Male; D008875:Middle Aged; D009339:Needles; D009407:Nerve Block / Q000295:instrumentation / Q000379:methods*; D011312:Pressure; D016037:Single-Blind Method
chemical_list: D000779:Anesthetics, Local